The electrophotography (EP) process used in some imaging devices, such as laser printers and copiers, is susceptible to variations due to environmental changes and component life. This variability may have a greater impact on color EP printers since it may cause changes in the toner density of developed images, which in turn causes objectionable color shifts. It is general practice in the industry to incorporate sensors that measure the toner density of test images and provide feedback to the control system for making adjustments to various bias voltages and/or laser power. Ideally, these adjustments increase or decrease the amount of toner developed out to the latent image to achieve a desired density. Some conventional sensors currently used in the industry are reflective sensors that range from a simple emitter-detector arrangement to more complex arrangements. For instance, some sensors incorporate light-integrating cavities and collimated light sources. A limiting factor of the known art is the ability to tune the sensor to the toner that is being measured. As an example, the color toners cyan, magenta, and yellow are transparent to infrared light and reflect light in a diffuse manner. Conversely, black toner, which often includes carbon black pigment, absorbs infrared light. This absorption results in a reduction of specular light reflected off the substrate. Accordingly, conventional sensors may not be optimally suited for use in color EP printers.